 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.texteditor;

 import java.util.HashMap ;
 import java.util.Iterator ;
 import java.util.Map ;

 import org.eclipse.jface.text.source.Annotation;

 import org.eclipse.ui.internal.editors.text.EditorsPlugin;
 import org.eclipse.ui.internal.texteditor.*;

 /**
  * Provides the strategy for finding the annotation preference for a given
  * annotation.
  *
  * @since 3.0
  */
 public class AnnotationPreferenceLookup {

     /** The map between annotation types and annotation preference fragments. */
     private Map fFragments;

     /**
      * Creates a new annotation preference lookup object.
      */
     public AnnotationPreferenceLookup() {
     }

     /**
      * Returns the annotation preference of a given annotation.
      *
      * @param annotation the annotation
      * @return the annotation preference for the given annotation or <code>null</code>
      */
     public AnnotationPreference getAnnotationPreference(Annotation annotation) {
         return getAnnotationPreference(annotation.getType());
     }

     /**
      * Returns the annotation preference defined for the given annotation type.
      *
      * @param annotationType the annotation type
      * @return the annotation preference for the given annotation type or <code>null</code>
      */
     public AnnotationPreference getAnnotationPreference(String annotationType) {
         if (annotationType == null || annotationType == Annotation.TYPE_UNKNOWN)
             return null;

         AnnotationTypeHierarchy hierarchy= getAnnotationTypeHierarchy();
         AnnotationType type= hierarchy.getAnnotationType(annotationType);
         AnnotationPreference preference= type.getPreference();
         if (preference == null) {
             preference= new DelegatingAnnotationPreference(type, this);
             type.setAnnotationPreference(preference);
         }

         return preference;
     }

     /**
      * Returns the annotation preference fragment defined for the given
      * annotation type.
      * <p>
      * For internal use only. Not intended to be called by clients.
      *
      * @param annotationType the annotation type
      * @return the defined annotation preference fragment
      */
     public AnnotationPreference getAnnotationPreferenceFragment(String annotationType) {
         Map fragments= getPreferenceFragments();
         return (AnnotationPreference) fragments.get(annotationType);
     }

     /**
      * Returns the annotation type hierarchy and creates it when not yet done.
      *
      * @return the annotation type hierarchy
      */
     private AnnotationTypeHierarchy getAnnotationTypeHierarchy() {
         return EditorsPlugin.getDefault().getAnnotationTypeHierarchy();
     }

     /**
      * Returns a map between annotation type names and annotation preference
      * fragments and creates it if not yet done.
      *
      * @return the map between annotation type names and annotation preference fragments
      */
     private synchronized Map getPreferenceFragments() {
         if (fFragments == null) {
             fFragments= new HashMap ();
             MarkerAnnotationPreferences p= new MarkerAnnotationPreferences();
             Iterator e= p.getAnnotationPreferenceFragments().iterator();
             while (e.hasNext()) {
                 AnnotationPreference fragment= (AnnotationPreference) e.next();
                 Object annotationType = fragment.getAnnotationType();
                 AnnotationPreference preference= (AnnotationPreference) fFragments.get(annotationType);
                 if (preference == null)
                     fFragments.put(annotationType, fragment);
                 else
                     preference.merge(fragment);
             }
         }
         return fFragments;
     }
 }

